Surface seal for arrangement on a component and a method of arranging a surface seal on a component

ABSTRACT

In order to produce a surface seal for arrangement on a component whose material has a thermal expansion differing from that of the material of the surface seal and which is mountable on the component in a simple manner over a large temperature range without the danger of fatigue, it is proposed that the surface seal be provided with compensating recesses each of which comprises at least one compensating region whose width, in the mounted state of the surface seal, alters with a change in temperature of the surface seal in such a way that the different thermal expansions of the surface seal and the component are at least partially (preferably, substantially completely) compensated.

RELATED APPLICATION

The present disclosure relates to the subject matter which was disclosed in the German patent application No. 10 2004 015 324.8 dated 30 Mar. 2004. The entire description of this earlier application is deemed to form a part of the subject matter of the present description (“incorporation by reference”).

FIELD OF THE DISCLOSURE

The present invention relates to a surface seal for arrangement on a component whose material has a thermal expansion differing from that of the material of the surface seal.

BACKGROUND

Large differences between the thermal expansions arise for example, if the surface seal is formed from a synthetic material, in particular from a fluoro-polymer, and the component, upon which the surface seal is to be arranged, is formed from a metallic material, from a steel for example.

Large differences in the thermal expansions of the surface seal and the component can entail leakages and premature fatiguing of the material of the surface seal. Moreover, the process of mounting the surface seal on the component is problematic. If the surface seal is designed in such a way that it is free of stress when resting on the component at an operating temperature higher than the ambient temperature and if it is arranged on the component at this higher temperature, then it will be extended beyond the elastic limit thereof due to its thermal contraction when cooling to the ambient temperature. During subsequent reheating to the operating temperature, the surface seal would then be uncontrollably warped.

By contrast, if the surface seal is placed on the component at ambient temperature, then it must be appropriately extended in this cold condition (by an order of magnitude of one per cent) for which an enormous amount of force is required.

Consequently, the object of the present invention is to produce a surface seal of the type mentioned hereinabove which is usable over a large temperature range without the danger of fatigue and which is adapted to be mounted on the component in a simple manner.

SUMMARY OF THE INVENTION

In accordance with the invention, this object is achieved in the case of a surface seal having the features indicated in the preamble of Claim 1 in that the surface seal is provided with compensating recesses each of which comprises at least one compensating region whose width, in the mounted state of the surface seal, alters with a change in the temperature of the surface seal in such a way that the different thermal expansions of the surface seal and the component are at least partially (preferably, substantially completely) compensated.

The concept underlying the solution in accordance with the invention is that of compensating the different thermal expansions of the surface seal and the component by totally or partially altering the dimensions of the compensating regions of the compensating recesses so that the elastic limit of the material of the surface seal is neither exceeded in the operative state nor at the ambient temperature.

The surface seal in accordance with the invention is usable over a large temperature range without the danger of fatigue and can be mounted on the component at the ambient temperature without an excessive amount of force due to the compensating effect of the compensating recesses.

In principle, the surface seal in accordance with the invention can be arranged on any surface of the component.

In particular, the surface seal can be provided for arrangement on a substantially flat surface of the component, for example, for arrangement on a flat sealing surface upon which a cover incorporating access openings slides back and forth.

In a preferred embodiment of the invention however, the surface seal is provided for arrangement on an outer surface of the component.

The component can, in particular, be substantially cylindrical.

In particular, provision may be made for the surface seal to encircle the component when in the mounted state.

It is particularly expedient if the surface seal is formed in one piece, since such a one-piece surface seal is manipulable in a particularly simple manner.

In order to be able to compensate an expansion in a peripheral direction of the component for different thermal expansions of the surface seal and the component, it is expedient if at least some of the compensating recesses each comprise at least one compensating region which has a longitudinal direction aligned transversely, preferably substantially perpendicularly, to a peripheral direction of the component.

Correspondingly, in order to be able to compensate for the different thermal expansions of the surface seal and the component in a direction that is transverse to the peripheral direction of the component, it is expedient if at least some of the compensating recesses each comprise at least one compensating region which has a longitudinal direction aligned substantially in parallel with the peripheral direction of the component.

In a preferred embodiment of the invention, provision is made for at least some of the compensating recesses to each comprise at least two compensating regions.

In order to be able to compensate for the different thermal expansions of the surface seal and the component in any direction, it is of advantage hereby if the at least two compensating regions of the same compensating recess have longitudinal directions aligned transversely, preferably substantially perpendicularly, with respect to one another.

Furthermore, it has proved to be expedient for at least some of the compensating recesses each to have a central region into which open the at least two compensating regions of the respective compensating recess.

In particular, provision may be made for the at least two compensating regions of the respective compensating recess which open into the central region of the compensating recess to have longitudinal directions aligned transversely, preferably substantially perpendicularly, with respect to one another.

If the component on which the surface seal is to be arranged has cavities, then, apart from the compensating recesses, it is advantageous for the surface seal to comprise access openings which are associated with the cavities in the component in the mounted state of the surface seal in order to enable external access to be made to these cavities.

If the surface seal comprises webs separating these access openings from each other, then it is advantageous for at least some of the compensating recesses of the surface seal to be arranged at the crossing regions of these webs.

In particular, if, apart from the compensating recesses, the surface seal does not comprise access openings arranged in a grid-like manner, then it is of advantage if the surface seal comprises at least one double row of compensating recesses, wherein the double row comprises a first row of compensating recesses and a second row of compensating recesses, the second row of compensating recesses is aligned substantially parallel to the first row of compensating recesses and the compensating recesses in the second row are displaced relative to the compensating recesses in the first row in the longitudinal direction of the rows.

In order to enable the thermal expansion of the surface seal to be compensated in at least two mutually transversely aligned directions, the surface seal preferably comprises at least two double rows of compensating recesses which extend transversely, preferably substantially perpendicularly, with respect to one another.

At least one double row is preferably provided for each expansion seal for which compensation of the thermal expansion is to be effected. However, the surface seal may also be provided with more than one double row per direction of expansion.

The material of the surface seal preferably comprises a synthetic material of low sliding friction. A fluoro-polymer or a fluoro-polymer compound is particularly suitable since these materials are chemically highly stable and are low in friction.

Claim 17 is directed toward a combination of a component and a surface seal in accordance with the invention arranged on the component, wherein the periphery of the component is provided with entrainment elements for tensioning the surface seal.

Such entrainment elements enable the surface seal to be placed on the component at the ambient temperature in a simple manner.

These entrainment elements are preferably moveable relative to the component.

In particular, provision may be made for the entrainment elements to be held on the component by means of fixing bolts.

Furthermore, the object of the present invention is to provide a method for arranging a surface seal on a component whose material has a thermal expansion differing from that of the material of the surface seal which can be carried out in a simple manner and without needing a large outlay on equipment.

This object is achieved by a method for arranging a surface seal on a component whose material has a thermal expansion differing from that of the material of the surface seal, wherein the surface seal is provided with compensating recesses each of which comprises at least one compensating region whose width, in the mounted state of the surface seal, alters with a change in the temperature of the surface seal in such a way that the differences in the thermal expansions of the surface seal and the component are reduced, preferably substantially compensated, wherein the method comprises the following process step:

-   -   arranging the surface seal on the component at a mounting         temperature which is different from an operating temperature of         the component, wherein the surface seal is subjected to a         mechanical tension and the compensating regions of at least some         of the compensating recesses alter in width due to the effect of         the mechanical tension.

In particular, the method in accordance with the invention enables the surface seal to be arranged on the component at the ambient temperature and to extend it in correspondence with the difference in the thermal expansions of the surface seal and the component without all the material of the surface seal needing to be extended for this purpose. Rathermore, in accordance with the method of the invention, it is sufficient to slightly deform the regions of the surface seal bordering the compensating recesses, and the greater part of the deformation necessary for the mounting of the surface seal is obtained by an alteration in the width of the compensating regions of the compensating recesses.

In a preferred embodiment of the method in accordance with the invention, provision is made for the width of the compensating regions of at least some of the compensating recesses to alter with a change of the temperature of the surface seal from the mounting temperature to the operating temperature.

In particular, provision may be made for the width of the compensating regions of at least some of the compensating recesses to be reduced with a change of the temperature of the surface seal from the mounting temperature to the operating temperature.

The mounting of the surface seal on the component is particularly simple, if the surface seal is tensioned during the mounting process by means of entrainment elements arranged on the component.

In particular, provision may be made for the surface seal to be subjected to a mechanical tensional force directed substantially parallel to a peripheral direction of the component at least intermittently during the process of mounting it on the component.

Alternatively or in addition thereto, provision may be made for the surface seal to be subjected to a mechanical tensional force directed substantially transversely, preferably substantially perpendicularly, to a peripheral direction of the component at least intermittently during the process of mounting it on the component.

In a preferred embodiment of the method in accordance with the invention, provision is made, in the course of the process of mounting it on the component, for the surface seal to be subjected to a mechanical tensional force directed substantially parallel to a peripheral direction of the component during one mounting phase and to be subjected to a mechanical tensional force directed substantially transversely, preferably substantially perpendicularly, to a peripheral direction of the component during another mounting phase.

In this way, it is possible to successively extend the surface seal by the requisite amount in a direction parallel to the peripheral direction of the component and in a direction transverse to the peripheral direction of the component.

The surface seal in accordance with the invention is particularly suitable for use in a processing device for treating work pieces which are transported through the processing device in receptacle chambers, wherein the surface seal seals the receptacle chambers with respect to each other and also with respect to the housing of the processing device.

Further features and advantages of the invention form the subject matter of the following description and the illustration of exemplary embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic horizontal cross section through a processing device;

FIG. 2 a schematic vertical longitudinal section through the processing device depicted in FIG. 1;

FIG. 3 a schematic illustration of a transfer device for transporting work pieces between two chamber levels of the processing device;

FIG. 4 a schematic vertical longitudinal section through the processing device, wherein a chamber drum of the processing device is lifted out of a housing for the processing device;

FIG. 5 a schematic development of a surface seal for the processing device in a cold mounting state;

FIG. 6 a schematic plan view of a compensating recess in the surface seal depicted in FIG. 5, whose compensating regions are widened when in the cold mounting state;

FIG. 7 a schematic development of the surface seal depicted in FIG. 5 in a warm operative state;

FIG. 8 a schematic plan view of a compensating recess in the surface seal, whose compensating regions are narrowed in the warm operative state;

FIG. 9 a detailed schematic plan view of the peripheral surface of a chamber drum of the processing device with a surface seal laid out on the chamber drum before the surface seal has been extended by entrainment elements of the chamber drum;

FIG. 10 a detailed schematic radial view through a boundary region of the chamber drum having the surface seal laid out thereon before the surface seal has been extended by means of the entrainment elements, wherein the line of sight is in the direction of the arrow 10 in FIG. 9;

FIG. 11 an illustration corresponding to that of FIG. 9, after the surface seal has been extended by means of the entrainment elements;

FIG. 12 an illustration corresponding to that of FIG. 10, after the surface seal has been extended by means of the entrainment elements, wherein the line of sight is in the direction of the arrow 12 in FIG. 11;

FIG. 13 a schematic illustration of a device for the rotation of a work piece in a receptacle chamber, wherein the rotating device comprises a drive shaft fed through a wall of the receptacle chamber;

FIG. 14 a schematic illustration of a rotating device for the rotation of a work piece in a receptacle chamber, wherein the rotating device is driven by frictional engagement with the housing of the processing device;

FIG. 15 a schematic horizontal section through one chamber level of the processing device which is designed as a vacuum lock;

FIG. 16 a schematic illustration of a device incorporating a shaft which extends through a partition wall from a first area filled with a first medium into a second area filled with a second medium, wherein the shaft is provided on its cylindrical outer surface with a ring-like surface seal for sealing between the two areas;

FIG. 17 a detail view of a schematic development of the surface seal depicted in FIG. 16 in a warm operative state;

FIG. 18 a detail view of a schematic development of the surface seal depicted in FIG. 16 when in a cold mounting state;

FIG. 19 a detail view of a schematic development of a further embodiment of the surface seal depicted in FIG. 16 in a warm operative state;

FIG. 20 a detail view of a schematic development of the further embodiment of a surface seal depicted in FIG. 19 when in a cold mounting state;

FIG. 21 a detail view of a schematic development of a further embodiment of the surface seal depicted in FIG. 16 in a warm operative state;

FIG. 22 a detail view of a schematic development of the further embodiment of a surface seal depicted in FIG. 21 when in a cold mounting state; and

FIG. 23 a schematic plan view of a surface seal incorporating two double rows of compensating recesses extending perpendicularly to each other.

Similar or functionally equivalent elements are designated by the same reference symbols in all the Figures.

DETAILED DESCRIPTION OF THE INVENTION

As illustrated in FIGS. 1 to 8, a processing device bearing the general reference 100 for treating work pieces 102 comprises a housing 104 having a circular disk-shaped base plate 106 and a hollow cylindrical housing wall 108 which extends upwardly from the upper face of the base plate 106 (see FIG. 2).

The base plate 106 of the housing 104 rests on a plurality of supports 110 which are supported on a (not illustrated) foundation.

The housing 104 is open upwardly.

A chamber drum bearing the general reference 112 which is rotatable about a substantially vertical axis of rotation 114 is arranged in the interior of the housing 104.

At the lower end thereof, the chamber drum 112 comprises a circular disk-shaped drum base plate 116, from the upper face whereof a hollow cylindrical, hollow shaft 118 that is aligned coaxially with respect to the drum base plate 116 extends in an upward direction.

The heights of the drum base plate 116 and the hollow shaft 118 together correspond substantially to the height of the housing wall 108.

From the outer surface of the hollow shaft 118, a plurality of circular disk-shaped ring-like base plates 120 and a circular disk-shaped ring-like cover plate 122 arranged at the upper end of the hollow shaft 118 extend outwardly in a radially horizontal direction, wherein the base plates 120 are spaced from each other, from the drum base plate 116 and from the cover plate 122 in the axial direction of the hollow shaft 118.

Furthermore, as is perceptible from FIG. 1, vertical partition walls 124 extend outwardly in the radial direction from the outer surface of the hollow shaft 118, wherein each of the partition walls 124 is arranged between two base plates 120, between a base plate 120 and the drum base plate 116 or between a base plate 120 and the cover plate 122 in each case.

A receptacle chamber 126 of the chamber drum 112 is bounded in each case by two vertical partition walls 124, by a section of the hollow shaft 118 and by two base plates 120 or by a base plate 120 and the drum base plate 116 or by a base plate 120 and the cover plate 122.

Those receptacle chambers 126 which are arranged at the same height in the chamber drum 112 together form one chamber level 128 of the chamber drum 112.

The exemplarily illustrated processing device 100 thus comprises a chamber drum 112 having six chamber levels 128, each of which comprises eight receptacle chambers 126.

However, the number of receptacle chambers 126 does not have to be the same in each chamber level 128; rathermore, the number of receptacle chambers per chamber level 128 can vary arbitrarily.

In particular, provision may be made for one or more of the partition walls 124 between successive receptacle chambers 126 to be dispensed with in one or in a plurality of the chamber levels.

Each of the receptacle chambers 126 in the same chamber level 128 and the receptacle chambers 126 in the different chamber levels 128 are connected to one another in a mutually non-rotatable manner so that they are rotatable together about the axis of rotation 114 of the chamber drum 112.

For the purposes of driving this rotary device, there serves a rotary drive which bears the general reference 130 and comprises a rotary drive motor 132, an electric geared motor for example, that is arranged on the lower surface of the base plate 106 of the housing 104.

The drive shaft 134 of the rotary drive motor 132 is passed through a central passage opening 136 in the base plate 106 of the housing 104 and is connected to the lower surface of the drum base plate 116 of the chamber drum 112 in mutually non-rotatable manner.

In order to enable the work pieces 102 to be inserted into the processing device 100, the housing wall 108 is provided with an e.g. square entry opening 138 a at the height of the uppermost chamber level 128 a. The extent of the entry opening 138 a corresponds substantially to the extent of the port opening 140 in each of the receptacle chambers 126 of the uppermost chamber level 128 a that is bounded by the vertical partition walls 124, the base plate 120 and the cover plate 122, so that the receptacle chambers 126 in the uppermost chamber level 128 a can be moved alternately into a loading position in which the port opening 140 of the respective receptacle chamber 126 is aligned with the entry opening 138 a in the housing wall 108, as is illustrated in FIG. 1 for the chamber 126 a.

After a work piece 102 requiring processing has been inserted through the entry opening 138 into the respective receptacle chamber 126 that is aligned with said entry opening 138, the receptacle chamber 126 concerned together with the work piece 102 arranged therein is rotated by the rotary movement of the chamber drum 112—continuously or stepwise—through an angle of rotation of less than 360 degrees about the axis of rotation 114 into a transfer position, in which the port opening 140 of the receptacle chamber 126 concerned is aligned with an outlet opening 142 which is likewise arranged in the housing wall 108 at the height of the uppermost chamber level 128 a. The receptacle chamber 126 g has just reached this transfer position in FIG. 1.

Preferably, the angular spacing between the outlet opening 142 and the entry opening 138 of a chamber level 128 corresponds to the peripheral angle over which one of the receptacle chambers 126 or a plurality of receptacle chambers 126 in this particular chamber level 128 extend.

The work piece 102 arranged in the receptacle chamber 126 can be subjected to any type of processing step in the path section between the entry opening 138 and the outlet opening 142.

Such processing steps may, for example, involve thermal treatments, and in particular annealing processes such as “soft-annealing” of tubes for example, or drying processes such as the drying of a lacquer coating on the work piece 102 for example.

Furthermore, the processing steps may, for example, involve the sandblasting of a work piece 102 or the plating of a work piece 102.

Other possible treatments of a work piece 102 are, for example, washing processes using aqueous liquids or liquids containing hydrocarbons and/or such treatments as must take place in an inert gas or in a vacuum.

The work piece 102 can be subjected to one or to a plurality of such processing steps in each chamber level 128.

If a processing medium is to be supplied to the receptacle chamber 126 for such a treatment, then this is effected via supply connecting-pieces 144 which are arranged on the housing wall 108 at the angular position which the receptacle chamber 126 is passing at the desired processing time. In order to extract a processing medium from a receptacle chamber 126, extracting connecting-pieces 146 are provided on the housing wall 108 at positions that are displaced with respect to the supply connecting-piece 144 associated therewith by an angle of rotation which corresponds to the desired duration of the process.

However, the extracting connecting-piece 146 for a processing medium do not necessarily have to be located at the same level as the supply connecting-pieces 144 for the same processing medium. Rathermore, provision may be made for a processing medium that is supplied at one level of the processing device 100 only to be extracted therefrom at a level directly or indirectly following the supply level.

In order to enable a work piece 102 to be transferred to a subsequent processing level after its passage through one level 128 of the processing device 100, the processing device 100 comprises a plurality of transfer devices 148 of which one is schematically illustrated in FIG. 3

The transfer device 148 comprises a housing 150 which is flanged to a mounting flange 152 of the housing 104 of the processing device 100 in fluid-tight manner.

The mounting flange 152 surrounds a region of the housing wall 108 which surrounds the outlet opening 142 of a first chamber level 128 a and an entry opening 138 of a second chamber level 128 b so that a closed chamber 154 connecting the outlet opening 142 to the entry opening 138 in fluid-tight manner is formed by the mounting flange 152, the housing 150 of the transfer device 148 and the housing wall 108 of the processing device 100.

Furthermore, the transfer device 148 comprises a device 156 for moving the work piece 102 which is arranged within the chamber 154.

The moving device 156 comprises a moveable work piece seating 158, in the form of a moveable fork 160 for example, which is adapted to be displaced in the vertical direction by means of a chain hoist 162.

For example, the chain hoist 162 comprises a tension chain 164 which is guided over a driven sprocket wheel 166 and two guide sprocket wheels 168.

The chain hoist 162 together with the fork 160 is adapted to be displaced in the radial direction of the chamber drum 112 by means of a pneumatic piston 170.

The pneumatic piston 170 is displaceable in a pneumatic cylinder 172 and the two end faces 174 thereof can be alternately subjected to a high gas pressure in order to move the chain hoist 162 together with the fork 160 arranged thereon towards the axis of rotation 114 of the chamber drum 112 and away from said axis of rotation 114.

The work piece 102 that is to be transferred from the chamber level 128 a to the chamber level 128 b rests on spacers 176 in the receptacle chamber 126 of the chamber level 128 a, said spacers being supported on the base of the receptacle chamber 126.

For the purposes of picking up the work piece 102, the fork 160 is raised to the height of the chamber level 128 a by means of the chain hoist 162.

Subsequently, the fork 160 is pushed between the spacers 176 and under the work piece 102 by means of the pneumatic piston 170.

Thereupon, the fork 160 is raised somewhat by means of the chain hoist 162 so that the work piece 102 now rests on the fork 160 and is lifted off the spacers 176 in the receptacle chamber 126.

The fork 160 together with the work piece 102 is then withdrawn from the receptacle chamber 126 of the chamber level 128 a by means of the pneumatic piston 170 and lowered to the entry height of the chamber level 128 b by means of the chain hoist 162.

Subsequently, the fork 160 together with the work piece 102 is slid into a receptacle chamber 126′ of the chamber level 128 b by means of the pneumatic piston 170.

By lowering the fork 160 by means of the chain hoist 162, the work piece 102 is placed on the spacers 176 on the base of the receptacle chamber 126′.

Subsequently, the pneumatic piston 170 completely withdraws the fork 160 from the receptacle chamber 126′, and the fork 160 is raised to the level of the chamber level 128 a by means of the chain hoist 162 in order to await and then remove the next work piece 102 from the chamber level 128 a.

Since the transfer device 148 is totally enclosed, a processing medium that has possibly been supplied at the chamber level 128 a can also flow on through the chamber 154 of the transfer device 148 into the chamber level 128 b.

Furthermore, pressure equalisation between the receptacle chambers of the chamber level 128 a and the chamber level 128 b also takes place so that, in particular, a vacuum produced in the chamber level 128 a will be maintained in the chamber level 128 b.

Following the transfer of a work piece 102 from one chamber level 128 a to the succeeding chamber level 128 b, this particular work piece 102 is then advanced at this chamber level 128 b through an angle of less than 360 degrees about the axis of rotation 114 to the outlet opening 142 of the chamber level 128 b by the rotation of the chamber drum 112.

The work piece 102 can be subjected to further processing steps in the receptacle chamber 126′ during its passage through this level of the processing device 100.

Upon reaching the outlet opening 142 of the chamber level 128 b, the work piece 102 is transferred to the entry opening 138 of a further chamber level 128 by means of a further transfer device 148 which can be formed in a manner corresponding to that of the previously described transfer device 148, or removed from the processing device 100 in the event that the chamber level 128 b is the last level through which the work piece 102 is to pass.

In the previously described exemplary embodiment, the levels of the processing device 100 run from top to bottom. It would also be equally possible however, for the work pieces 102 to firstly enter the lowermost chamber level 128 f and for the work pieces 102 to then be advanced through the processing device 100 from bottom to top up to the uppermost chamber level 128 a and for them to be removed from the processing device 100 at this level.

In particular, if liquid or gaseous processing media are used in the processing device 100 and/or if a vacuum is produced within the processing device 100, then it is necessary for a surface seal 178 to be provided between the outer surface of the chamber drum 112 and the inner surface of the housing wall 108 for preventing a liquid or gaseous medium from flowing from a receptacle chamber 126 into the vertically or horizontally neighbouring receptacle chambers 126 or into the environment.

This surface seal 178 is arranged on the peripheral surface of the chamber drum 112 in mutually non-rotatable manner and moves together with the chamber drum 112 through the interior of the housing 104 of the processing device 100.

The surface seal 178 is designed as a one piece wrap-around foil seal.

A development of the surface seal 178 placed on the chamber drum 112 in a cold mounting state (at the ambient temperature) is illustrated in FIG. 5.

A development of the surface seal 178 in a warm operative state (at an operating temperature of 120° C. for example) is illustrated in FIG. 7.

The surface seal 178 is produced in the form of a foil of a sealing material which is made of a fluoro-polymer synthetic material or a fluoro-polymer compound. In particular, the surface seal 178 can be in the form of a polytetrafluoroethylene (PTFE) foil.

As can be perceived from FIGS. 5 and 7, the surface seal 178 is provided with substantially rectangular passage openings 180 which are each substantially congruent with a port opening 140 of a receptacle chamber 126 in the state wherein the surface seal 178 is located on the chamber drum 112.

In consequence, the passage openings 180 are arranged in a regular grid, wherein the number of superimposed rows 182 corresponds to the number of chamber levels 128 in the processing device 100 and the number of columns 184 in the grid corresponds to the number of receptacle chambers 126 per chamber level 128.

The passage openings 180 of the surface seals 178 are separated from one another by vertical webs 186 and by horizontal webs 188, wherein the horizontal webs 188 and the vertical webs 186 intersect in approximately square crossing regions 190.

In the mounted state of the surface seal 178, the horizontal webs 188 extend in the peripheral direction 187 of the chamber drum 112 and the vertical webs 186 extend in the axial direction 189 of the chamber drum 112.

As can best be perceived from FIGS. 5 and 6, the surface seal 178 is provided with a respective compensating recess 192 in each crossing region 190, said compensating recess comprising a substantially circular central region 193 from which two vertical compensating regions 194 in the form of vertical slits extend respectively upwardly and downwardly and from which two horizontal compensating regions 196 in the form of horizontal slits extend respectively to the left and to the right.

The passage openings 180 and the compensating recesses 192 are separated out from a substantially flat foil of the sealing material by a suitable separating process, by being punched out or cut out for example.

In a concrete exemplary embodiment, the thickness of the surface seal 178 amounts to approximately 5 mm. The height of the chamber drum 112 and thus the height H of the surface seal 178 amount to approximately 1,000 mm for example. The diameter of the chamber drum 112 amounts to approximately 800 mm for example, so that the periphery of the chamber drum 112 and thus the length L of the surface seal 178 amount to approximately 2,513 mm. Furthermore, six chamber levels 128 and eight receptacle chambers 126 per chamber level 128 are provided in the exemplary embodiment, so that the width of the vertical webs 186 and that of the horizontal webs 188 amounts to approximately 30 mm in each case.

The horizontal extent I and the vertical extent h of the compensating recesses 192 is preferably greater than the respective widths of the vertical webs 186 and the horizontal webs 188.

In a concrete exemplary embodiment, the vertical extent h of the compensating recesses 192 amounts to approximately 40 mm for example. In the same exemplary embodiment, the horizontal extent I of the compensating recesses 192 likewise amounts to approximately 40 mm for example.

The material of the surface seal 178 (PTFE or a PTFE compound for example) has a significantly higher coefficient of thermal expansion than the material of the chamber drum 112 (usually a metallic material, and in particular, a steel). Consequently, the surface seal 178 extends by approximately 1 per cent relative to the peripheral surface of the chamber drum 112 when heated from the ambient temperature to an operating temperature of approximately 120° C. for example, thus, in the case of the previously described concrete exemplary embodiment, by approximately 25 mm in the peripheral direction of the chamber drum 112 and by approximately 10 mm in the axial direction of the chamber drum 112.

This difference in the thermal expansions of the surface seal 178 on the one hand and of the chamber drum 112 on the other is compensated by the compensating recesses 192 provided in the crossing regions 190 of the surface seal 178.

As is perceptible from FIGS. 5 and 6, the surface seal 178 placed on the chamber drum 112 in the mounted state (at the ambient temperature) is subjected to a mechanical prestressing due to which the compensating regions 194, 196 of the compensating recesses 192 are widened.

In particular, the vertical compensating regions 194 widen out from their pointed peaks 198 up to the point where they open into the central region of the compensating recess 192 whereat the width b₁ is approximately 3 mm for example. In the mounted state at the ambient temperature, the horizontal compensating regions 196 widen out from their respective peaks 200 up to the point where they open into the central region 193 of the compensating recess 192 whereat the width b₂ is approximately 1.5 mm for example.

Due to the greater thermal expansion of the surface seal 178 relative to the chamber drum 112 when heated from the ambient temperature to the operating temperature of approximately 120° C. for example, the width of the vertical compensating regions 194 and that of the horizontal compensating regions 196 reduces during the process of heating the chamber drum 112 and the surface seal 178 up to the operating temperature so that the width b₁ of the vertical compensating regions 194 and the width b₂ of the horizontal compensating regions 196 is approximately equal to zero in the operative state (see FIG. 8).

Thus, in the operative state, the surface seal 178 rests on the outer surface of the chamber drum 112 such that it is substantially free of tension, and in particular, there are no tensions effective in the peripheral direction 187 of the chamber drum 112 or in the axial direction 189 of the chamber drum 112. In this way, the surface seal 178 can be used over a large operating temperature range without the danger of fatigue.

The surface seal 178 can be stretched out on the chamber drum 112 in a simple manner at the manufacturing stage of the processing device 100 or when it becomes necessary to replace it after a certain period of operation.

For this purpose, the chamber drum 112 is firstly lifted out of the housing 104 of the processing device 100 in an upward direction as illustrated in FIG. 4.

For this purpose, one can use a lifting device which bears the general reference 202 and comprises a plurality of support rings 204 that are fixed to the upper surface of the cover plate 122, a supporting cord 206 being pulled through each of these rings. The upper ends of the supporting cords 206 are connected to the lower end of a bearing cable 210 at the point 208, said cable being led over a stationary guide roller 212 and being adapted to be raised or lowered by means of a (not illustrated) motor driven cable winch in order to lift the chamber drum 112 out of the housing 104 or to lower the chamber drum 112 back down again.

The dimensions of the surface seal 178 are designed for the warm operative state, i.e. they are such that the vertical and horizontal slits of the compensating recesses 192 are closed in the warm operative state.

In principle, the surface seal 178 can then be laid out on the chamber drum 112 at the operating temperature. For this purpose however, the chamber drum 112 and the surface seal 178 must be heated up to the operating temperature outside the housing 104 of the processing device, this being something that cannot be done at all or can only be done with difficulty—in particular, in the event of replacing a surface seal 178 in the course of a maintenance procedure for the processing device 100.

However, as an alternative thereto, the surface seal 178 could also be first laid loosely on the cold chamber drum 112 in the cold state and then be successively extended in the peripheral direction 187 and in the axial direction 189 of the chamber drum 112.

The extension of the surface seal 178 in the peripheral direction 187 of the chamber drum 112 is effected by means of vertical entrainment metal sheets 214 (see FIG. 9) which, in each case, are held on one of the partition walls 124 of the chamber drum 112, namely, in the vicinity of the port opening 140 of a receptacle chamber 126, by means of a plurality, two for example, of fixing bolts 216 whose shanks each pass through a respective passage hole 220 in the vertical entrainment metal sheet 214 and engage in vertical, mutually spaced, threaded blind holes 218, whereby an outer edge 222 of the respective entrainment metal sheet 214 projects outwardly in the radial direction of the chamber drum 112 beyond the particular partition wall 124 by a distance d which is smaller than the thickness of the surface seal 178, for example, by approximately 3 mm (see FIG. 10).

The requisite extension of the surface seal 178 in the axial direction 189 of the chamber drum 112 is effected by means of horizontal entrainment metal sheets 224 which are each held on the appertaining base wall or the cover wall of the receptacle chamber 126, namely close to the port opening 140 of the receptacle chamber 126, by means of a plurality, four for example, of fixing bolts 216 which pass through passage holes 220 in the horizontal entrainment metal sheet 224 and are screwed into threaded blind holes 218 in the base wall or the cover wall of a receptacle chamber 126, whereby an outer edge 222 of the horizontal entrainment metal sheet 224 projects outwardly in the radial direction of the chamber drum 112 beyond the particular base plate 120, 116 or cover plate 122 of the chamber drum 112 by a distance d′ which is smaller than the thickness of the surface seal 178, for example, by approximately 3 mm.

At the ambient temperature, the length L of the surface seal 178 is shorter (by 25 mm for example) than the periphery of the chamber drum 112 and the height H of the surface seal is smaller (by 10 mm for example) than the height of the chamber drum 112.

In the cold pre-mounting state of the surface seal, in which the surface seal 178 is not subjected to external tensions, the compensating regions 194, 196 of the compensating recesses 192 of the surface seal 178 are closed (in like manner to the warm operative state).

For the purposes of mounting the surface seal 178 on the chamber drum 112, the surface seal 178 is firstly placed with the aid of one of its vertical webs 186 on a row of partition walls 124 of the chamber drum 112 that are arranged one below the other and is fastened to the chamber drum 112 at this web 186 by means of the vertical entrainment metal sheets 214 adjacent thereto, in that the fixing bolts 216 of the relevant vertical entrainment metal sheets 214 are fully tightened until the entrainment metal sheets 214 rest flatly against the particular partition wall 124.

Initially, the remainder of the surface seal 178 is only drawn loosely around the chamber drum 112 so that a gap of at least 25 mm in width remains between the ends of the surface seal 178.

Starting from the first vertical web 186 with the aid of which the surface seal 178 was fastened to the chamber drum 112, the surface seal 178 is stretched at the vertical web 186′ adjacent thereto in the peripheral direction 187 of the chamber drum by the anticipated thermal expansion, in that the fixing bolts 216 of the vertical entrainment metal sheets 214, which adjoin the vertical web 186′ and are initially still projecting by approximately 4 mm from the relevant partition wall 124 (see FIG. 9), are fully tightened (see FIG. 11) until the vertical entrainment metal sheets 214 associated therewith rest flatly against the relevant partition wall 124. The surface seal 178 is thereby pulled apart at the vertical compensating regions 194 of the compensating recesses 192 arranged on the webs 186 and thus stretched in the peripheral direction 187 of the chamber drum 112.

Since here only narrow web regions of the surface seal 178 located near the vertical compensating regions 194 are lightly deformed, this extension of the surface seal 178 is coupled with a far smaller expenditure of force than would be the case if all the vertical webs 186 had to be stretched by the same amount (by approximately 3 mm for example) from the material thereof over their entire width, by approximately 30 mm for example.

In the same manner as previously described, the surface seal 178 is fixed to the chamber drum 112 with the aid of the vertical webs following the vertical web 186′ in the peripheral direction 187 of the chamber drum the 112.

Subsequently, the surface seal 178 is successively extended in the axial direction 189 of the chamber drum 112.

To this end, the surface seal 178 is fastened to a base plate 120 of the chamber drum 112 with the aid of a horizontal web 188, in that the fixing bolts 216 of the neighbouring horizontal entrainment metal sheets 224 are fully tightened until the relevant horizontal entrainment metal sheets 224 rest flatly against the respective upper surface or lower surface of the particular base plate 120.

Subsequently, the surface seal 178 is stretched in the axial direction 189 of the chamber drum 112, in that a horizontal web 188′ neighbouring the first horizontal web 188 in the vertical direction is fastened to a vertically neighbouring base plate 120′, namely, by fully tightening the fixing bolts 216 of the horizontal entrainment metal sheets 224 adjoining the horizontal web 188′ until these entrainment metal sheets 224 also rest flatly against the respective lower surface or the upper surface of the base plate 120′.

The surface seal 178 is thereby pulled apart at the horizontal compensating regions 196 of the compensating recesses 192 which are arranged in the vicinity of the horizontal web 188, whereby the surface seal 178 is extended in the axial direction 189 of the chamber drum 112 by the anticipated thermal expansion.

The extension of the surface seal 178 in the axial direction 189 is then continued, in that the surface seal 178 is fixed to a further base plate 120 or to the cover plate 122 or to the drum base plate 116 of the chamber drum 112 with the aid of a further horizontal web following the web 188′ in the axial direction 189.

The process of mounting the surface seal 178 on the chamber drum 112 comes to an end when all the vertical webs 186 and all the horizontal webs 188 of the surface seal 178 are fixed to the chamber drum 112 by means of the entrainment metal sheets 214, 224 and thus the surface seal 178 is clamped in its entirety to the chamber drum 112.

Subsequently, the chamber drum 112 can be reinserted into the housing 104 of the processing device 100 by means of the lifting device 202.

In a second embodiment of the processing device 100 illustrated in FIG. 13, the work pieces 102 passing through the processing device 100 do not rest on stationary spacers 176 in at least one receptacle chamber 126, but rather, they are accommodated in a work piece retaining means 226 which is rotatable about an axis of rotation 228 that is aligned radially with respect to the axis of rotation 114 of the chamber drum 112.

Hereby, the rotation about the axis of rotation 228 is effected by means of a rotary shaft 230 which is fixed to a radially inner end face 232 of the work piece retaining means 226 and is rotatably mounted on the hollow shaft 118 of the chamber drum 112.

The end of the rotary shaft 230 located within the hollow shaft 118 is provided with a bevel gear 234 which engages a stationary central bevel gear 236 that is aligned coaxially with respect to the axis of rotation 114 of the chamber drum 112 and is connected to the upper face of the base plate 106 of the housing 104 of the processing device 100 by a vertical supporting tube 238 which passes through a passage boring 240 in the drum base plate 116.

As a consequence of a rotational movement of the hollow shaft 118 about the axis of rotation 114 of the chamber drum 112, the bevel gear 234 meshed with the stationary central bevel gear 236 and hence the work piece retaining means 226 together with the work piece 102 accommodated therein rotate about the horizontal axis of rotation 228.

In order to enable the work piece 102 to be removed from the work piece retaining means 226 by means of a transfer device 148, there are provided a plurality of spacers 242 on the work piece retaining means 226 so that a moveable work piece seating 158 of the transfer device 148, a moveable fork 160 for example, can be moved into the space between the work piece 102 and a wall of the work piece retaining means 226 in order to lift the work piece 202 from the spacers 242 and move it out of the work piece retaining means 226.

In order to decouple the rotational speed of the work piece retaining means 226 in the receptacle chambers 126 from the rotational speed of the chamber drum 112 about the axis of rotation 114, provision could also be made for the central bevel gear 236, which is coaxial with the axis of rotation 114, not to be fixed, but rather to be mounted such that it is rotatable relative to the housing 104 and comprise its own rotary drive.

In all other respects, the second embodiment of a processing device 100 is identical to that of the first embodiment in regard to the structure and functioning thereof, and insofar reference should be made to the previous description.

A third embodiment of a processing device 100 illustrated in FIG. 14 differs from the first embodiment in that the work pieces 102 do not rest on stationary spacers 176 in at least one receptacle chamber 126 of the chamber drum 112, but rather, are held in a work piece retaining means 246 which is rotatable about an axis of rotation 244 that is aligned in parallel with the axis of rotation 114 of the chamber drum 112.

The work piece retaining means 246 comprises a turntable 248 having spacers 250, upon which the respective work piece 102 rests, arranged on its upper surface.

The lower surface of the turntable 248 is connected to a friction wheel 254 by a rotary shaft 252 which is mounted in rotatable manner (by means of a not illustrated bearing) on the base of the receptacle chamber 126 and is aligned coaxially with respect to the axis of rotation 244, the peripheral surface of the friction wheel being in contact with the inner surface of the housing wall 108 of the housing 104 of the processing device 100.

In the course of a rotary movement of the chamber drum 112 about the axis of rotation 114, the friction wheel 254 rolls on the inner surface of the housing wall 108 due to the frictional engagement between the friction wheel 254 and the housing wall 108, whereby the friction wheel 254 and hence the work piece retaining means 246 are caused to rotate about the axis of rotation 244.

The spacers 250 of the work piece retaining means 246 enable a moveable work piece seating 158 of a transfer device 148 to be moved between the turntable 248 and the work piece 102 in order to lift the work piece 102 off the spacers 250 and then move it out of the receptacle chamber 126.

In all other respects, the third embodiment of a processing device 100 is identical to that of the first embodiment in regard to the structure and functioning thereof, and insofar reference should be made to the previous description.

In the case of a fourth embodiment of a processing device 100 which is illustrated in FIG. 15, at least one level of the processing device 100 functions as a vacuum lock.

In the exemplary embodiment illustrated in FIG. 15, the relevant chamber level 128 is provided with 16 receptacle chambers 126 which, due to the rotary movement of the chamber drum 112 about the axis of rotation 114, are moved from the entry opening 138 of the chamber level 128, through which the chamber level 128 is connected to the surrounding atmosphere and through which the work pieces 102 are inserted into the chamber level 128, to the outlet opening 142 of the chamber level 128 which is opposite the entry opening 138 at an angle of 180 degrees with respect thereto and whereat the vacuum pressure of the chamber level 128 is reached and through which said outlet opening the chamber level 128 is connected to a succeeding chamber 128 that is likewise at least partially evacuated.

Due to the rotary movement of the chamber drum 112, the receptacle chambers 126 are moved back—after the withdrawal of the work pieces 102 through the outlet opening 142—to the entry opening 138 in an empty state.

Thus, at this level, each receptacle chamber 126 always moves from a zone of high pressure (the entry opening 138) to a zone of vacuum pressure (the outlet opening 142) and then back again.

In the case of the vacuum lock illustrated in FIG. 15, the vacuum is produced in step-like manner, in that an empty receptacle chamber 126, in which there is still a vacuum, is short-circuited in a gaseous sense to a receptacle chamber equipped with a work piece 102 in which the vacuum pressure has not yet been reached.

For this purpose, the housing wall 108 is provided with a first air extracting connecting-piece 256 a on a part thereof following the entry opening 138 (as seen in the direction of rotation 255), said first air extracting connecting-piece being connected via a first short-circuiting pipeline 258 a to a first air supply connecting-piece 260 a which is arranged on the housing wall 108 after the outlet opening 142 and before the entry opening 138 (as seen in the direction of rotation 255).

A second air extracting connecting-piece 256 b that is arranged after the first air extracting connecting-piece 256 a (as seen in the direction of rotation 255) is connected via a second short-circuiting pipeline 258 b to a second air supply connecting-piece 260 b which is arranged before the first air supply connecting-piece 260 a (as seen in the direction of rotation 255).

A third air extracting connecting-piece 256 c that is arranged after the second air extracting connecting-piece 256 b (as seen in the direction of rotation 255) is connected via a third short-circuiting pipeline 258 c to a third air supply connecting-piece 260 c which is arranged before the second air supply connecting-piece 260 b (as seen in the direction of rotation 255).

A fourth air extracting connecting-piece 256 d that is arranged after the third air extracting connecting-piece 256 c (as seen in the direction of rotation 255) is connected via a fourth short-circuiting pipeline 258 d to a fourth air supply connecting-piece 260 d which is arranged before the third air supply connecting-piece 260 c (as seen in the direction of rotation 255).

A fifth air extracting connecting-piece 256 e, which is connected via a suction pipeline 262 to a (not illustrated) vacuum pump, is arranged between the fourth air extracting connecting-piece 256 d and the outlet opening 142 of the chamber level 128.

A fifth air supply connecting-piece 260 e that is arranged between the first air supply connecting-piece 260 a and the entry opening 138 of the chamber level 128 opens into the surrounding atmosphere so that, on each occasion, the particular receptacle chamber 126 that is located in the vicinity of the fifth air supply connecting-piece 260 e is adapted to be vented to atmospheric pressure via the fifth air supply connecting-piece 260 e.

Thus, in the case of the previously described chamber level 128 serving as a vacuum lock, a short-circuiting process between a not yet completely evacuated receptacle chamber 126, which is located in the path from the entry opening 138 to the outlet opening 142, and a not yet completely ventilated receptacle chamber 126, which is located in the path from the outlet opening 142 back to the entry opening 138, is carried out for a total of four times.

On the basis of an atmospheric pressure of 1,000 mbar for example and a desired vacuum pressure of 10 mbar for example, the chamber pressure still amounts to approximately 800 mbar after the pressure equalising process via the first short-circuiting pipeline 258 a for example, still amounts to approximately 600 mbar after the pressure equalising process via the second short-circuiting pipeline 258 b for example, still amounts to approximately 400 mbar after the pressure equalising process via the third short-circuiting pipeline 258 c for example and still amounts to approximately 200 mbar for example after the pressure equalising process via the fourth short-circuiting pipeline 258 d.

Consequently, the vacuum pump has to pump out the receptacle chamber 126 in the vicinity of the fifth air extracting connecting-piece 256 e from a pressure of only approximately 200 mbar in order to achieve the desired vacuum pressure of 10 mbar.

The vacuum pump thus has to evacuate a significantly lower amount of gas from the receptacle chambers 126 by virtue of this multi-stage evacuation process.

Moreover, for the production of the vacuum in a receptacle chamber 126, there is a significantly extended period of time available for producing the vacuum (for example, five successive work piece time periods when using 16 chambers in the chamber level 128 serving as a vacuum lock).

Furthermore, the difference of pressure, and thus the leakage rate via the surface seal 178 between the receptacle chambers 126 succeeding one another in the peripheral direction 187 of the chamber drum 112, is also reduced by the multi-stage evacuation process.

In all other respects the fourth embodiment of a processing device agrees 100 is identical to that of the first embodiment in regard to the structure and functioning thereof, and insofar reference should be made to the previous description.

A further embodiment of a device 300 including a surface seal 178 which comprises compensating recesses 192 for thermal expansion compensation purposes is illustrated in FIGS. 16 to 18.

The device 300 comprises a stationary partition wall 302 which separates a first space 304 that is filled with a first medium, oil for example, from a second space 306 that is filled with a second medium, air for example.

The partition wall 102 is provided with a passage opening 308 through which a shaft 310 that is rotatable about the longitudinal axis thereof extends from the first space 304 into the second space 306.

In order to keep the media with which the first space 304 and the second space 306 are filled separated from one another, the cylindrical outer surface 312 of the shaft 310 in the vicinity of the passage opening 308 is provided with an annular surface seal 178 whose outer face 314 remote from the shaft 310 adjoins the bounding surfaces 316 of the passage opening 308 and slides on these bounding surfaces 316 when the shaft 310 is rotating.

The shaft 310 consists of a metallic material, and the annular surface seal 178 is formed from a fluoro-polymer or from a fluoro-polymer compound which has a higher coefficient of thermal expansion than that of the metallic material of the shaft 310.

In order to enable the different thermal expansions of the material of the shaft 310 and the material of the surface seal 178 to be compensated in the peripheral direction of the shaft 310 in the course of a change from the cold mounting state (see FIG. 18) to the warm operative state (see FIG. 17), the surface seal 178 is provide with a plurality of compensating recesses 192 which are in the form of slits 318 extending in the axial direction of the shaft 310 in the warm operative state. These compensating recesses 192 are arranged in compensation regions 320 of the surface seal 178 which are mutually spaced along the periphery of the surface seal 178 and connected to one another by connecting webs 322.

Hereby, the width B i.e. the axial extent of the compensation regions 320 is more than twice as great as the width b i.e. the axial extent of the intermediary connecting webs 322.

In the process of cooling from the high operating temperature (see FIG. 17) to the lower mounting temperature (see FIG. 18), the compensating recesses 192 widen in the peripheral direction of the surface seal 178 and the shaft 310 due to the tensile stresses which are exerted by the connecting webs 322 on the compensation regions 320 of the surface seal 178, since the material of the surface seal 178 contracts to a greater extent than the material of the shaft 310 in the course of this decrease in temperature. Consequently, the compensating recesses 192 are substantially in the form of a rhomboid in the cold mounting state.

In a variant of the previously described ring-like surface seal 178 which is illustrated in FIGS. 19 to 20, the compensation regions 320 of the surface seal 178 are not substantially rectangular in the warm operative state as was the case in the previously described embodiment, but rather, are in the form of a hexagon.

Furthermore, in this embodiment, the compensating recesses 192 are formed in such a way that they already have a rhombic shape at the high operating temperature (see FIG. 19).

During the process of cooling to the lower mounting temperature (see FIG. 20), the extent of the compensating recesses 192 increases in the peripheral direction of the surface seal 178 and the shaft 310, whereas the axial extent of the compensating recesses 192 decreases so that the compensating recesses 192 take the form of flattened lozenges and the compensation regions 320 of the surface seal 178 adopt the form of flattened hexagons.

In a further embodiment of a ring-like face seal 178 for a shaft 310 which is illustrated in FIGS. 21 and 22, not just one respective compensating recess 192 is arranged in each compensation region 320 of the surface seal 178, but there is a plurality of such compensating recesses 192 which form a double row 324 extending in the axial direction of the surface seal 178 and the shaft 310.

A first row 326 of this double row 324 comprises a plurality, three for example, of compensating recesses 192 which are substantially in the form of a slit at the operating temperature and are mutually spaced in the axial direction of the surface seal 178.

A second row 328 of the double row 324 likewise comprises a plurality, two for example, of compensating recesses 192 which are substantially in the form of a slit at the operating temperature and are likewise mutually spaced in the axial direction of the surface seal 178.

The compensating recesses 192 of the second row 328 are thereby spaced in the peripheral direction of the surface seal 178 from the compensating recesses 192 of the first row 326 and are displaced relative to the compensating recesses 192 of the first row 326 in the axial direction of the surface seal 178, namely, preferably in such a manner that the centre of a compensating recess 192 of the second row 328 is approximately at the same axial position as the centre of the intervening space between two compensating recesses 192 of the first row 326 in each case.

In the course of cooling from the operating temperature to the lower mounting temperature (see FIG. 22), the compensating recesses 192 of the double row 324 widen in the peripheral direction of the surface seal 178 and the shaft 310 so that the compensating recesses 192 are approximately in the form of a triangle in the mounting state.

The annular surface seals 178 described above with reference to FIGS. 16 to 22 are especially suitable for arrangement on shafts 310 having a very large diameter.

These annular surface seals 178 extend to a significantly lesser extent in the axial direction thereof than in the peripheral direction thereof.

However, the principle of arranging the compensating recesses 192 in double rows 324 explained above in connection with FIGS. 21 and 22 can also be readily used in the case of such surface seals 178 as extend to a large extent in two mutually perpendicular directions as is illustrated in FIG. 23.

The surface seal illustrated in FIG. 23 comprises a first double row 324 a of compensating recesses 192 that are substantially in the form of a slit in the warm operative state and a second double row 324 b of compensating recesses 192 that are substantially in the form of a slit in the warm operative state, whereby the double row 324 b extends transversely, preferably substantially perpendicularly, to the double row 324 a so that a process of compensating for the thermal expansion of the surface seal 178 can be effected in two directions extending transversely relative to each other.

Naturally, more than two row of compensating recesses 192 could also be provided in each of these directions extending transversely relative to one another.

As is perceptible from FIG. 23, provision may be made, in particular, for the compensating recesses 192 of the one double row 324 a to cross compensating recesses 192 of the second double row 324 b.

The arrangement of the compensating recesses 192 in double rows 324 a, 324 b is to be particularly recommended if the surface seal 178 does not comprise passage openings 180 arranged in a grid-like manner as was the case for the surface seal 178 illustrated in FIGS. 5 and 7.

The compensating recesses 192 of the surface seals 178 shown in FIGS. 16 to 23 each comprise a compensating region whose width alters with a change of the temperature in such a way that the different respective thermal expansions of the surface seal 178 and the component 112 are at least partially compensated. 

1. A surface seal for arrangement on a component whose material has a thermal expansion differing from that of the material of the surface seal, wherein the surface seal is provided with compensating recesses each of which comprises at least one compensating region whose width, in the mounted state of the surface seal, alters with a change in the temperature of the surface seal in such a way that the different thermal expansions of the surface seal and the component are at least partially compensated.
 2. A surface seal in accordance with claim 1, wherein the surface seal is provided for arrangement on a substantially flat surface of the component.
 3. A surface seal in accordance with claim 1, wherein the surface seal is provided for arrangement on an outer surface of the component.
 4. A surface seal in accordance with claim 1, wherein the surface seal surrounds the component in ring-like manner when in the mounted state.
 5. A surface seal in accordance with claim 1, wherein the surface seal is formed in one piece.
 6. A surface seal in accordance with claim 1, wherein at least some of the compensating recesses each comprise at least one compensating region which has a longitudinal direction aligned transversely, preferably substantially perpendicularly, to a peripheral direction of the component.
 7. A surface seal in accordance with claim 1, wherein at least some of the compensating recesses each comprise at least one compensating region which has a longitudinal direction aligned substantially in parallel with the peripheral direction of the component.
 8. A surface seal in accordance with claim 1, wherein at least some of the compensating recesses each comprise at least two compensating regions.
 9. A surface seal in accordance with claim 8, wherein at least some of the compensating recesses each comprise two compensating regions which have longitudinal directions aligned transversely, preferably substantially perpendicularly, with respect to one another.
 10. A surface seal in accordance with claim 1, wherein at least some of the compensating recesses each comprise a central region into which open the at least two compensating regions of the respective compensating recess.
 11. A surface seal in accordance with claim of 10, wherein at least some of the compensating recesses each comprise a central region into which open at least two compensating regions of the respective compensating recess, wherein these compensating regions have longitudinal directions aligned transversely, preferably substantially perpendicularly, with respect to one another.
 12. A surface seal in accordance with claim 1, wherein, apart from the compensating recesses, the surface seal comprises access openings which are associated with cavities in the component in the mounted state of the surface seal.
 13. A surface seal in accordance with claim 12, wherein the surface seal comprises webs separating the access openings from each other and wherein at least some of the compensating recesses are arranged at the crossing regions of the webs.
 14. A surface seal in accordance with claim 1, wherein the surface seal comprises at least one double row of compensating recesses, wherein the double row comprises a first row of compensating recesses and a second row of compensating recesses, the second row of compensating recesses is aligned substantially parallel to the first row of compensating recesses and the compensating recesses in the second row are displaced relative to the compensating recesses in the first row in the longitudinal direction of the rows.
 15. A surface seal in accordance with claim 14, wherein the surface seal comprises at least two double rows of compensating recesses which extend transversely, preferably substantially perpendicularly, with respect to one another.
 16. A surface seal in accordance with claim 1, wherein the material of the surface seal comprises a synthetic material of low sliding friction, preferably, a fluoro-polymer or a fluoro-polymer compound.
 17. A combination of a component and a surface seal arranged on the component in accordance with claim 1, wherein the periphery of the component is provided with entrainment elements for tensioning the surface seal.
 18. A combination in accordance with claim 17, wherein the entrainment elements are moveable relative to the component.
 19. A combination in accordance with claim 17, wherein the entrainment elements are held on the component by means of fixing bolts.
 20. A method for arranging a surface seal on a component whose material has a thermal expansion differing from that of the material of the surface seal, wherein the surface seal is provided with compensating recesses each of which comprises at least one compensating region whose width, in the mounted state of the surface seal, alters with a change in the temperature of the surface seal in such a way that the differences in the thermal expansions of the surface seal and the component are reduced, preferably substantially compensated, comprising the following process step: arranging the surface seal on the component at a mounting temperature which is different from an operating temperature of the component, wherein the surface seal is subjected to a mechanical tension and the compensating regions of at least some of the compensating recesses alter in width due to the effect of the mechanical tension.
 21. A method in accordance with claim 20, wherein the width of the compensating regions of at least some of the compensating recesses alters with a change of the temperature of the surface seal from the mounting temperature to the operating temperature.
 22. A method in accordance with claim 21, wherein the width of the compensating regions of at least some of the compensating recesses is reduced with a change of the temperature of the surface seal from the mounting temperature to the operating temperature.
 23. A method in accordance with claim 20, wherein the surface seal is tensioned during the mounting process by means of entrainment elements arranged on the component.
 24. A method in accordance with claim 20, wherein the surface seal is subjected to a mechanical tensional force directed substantially parallel to a peripheral direction of the component at least intermittently during the process of mounting it on the component.
 25. A method in accordance with claim 20, wherein the surface seal is subjected to a mechanical tensional force directed substantially transversely, preferably substantially perpendicularly, to a peripheral direction of the component at least intermittently during the process of mounting it on the component.
 26. A method in accordance with claim 20, wherein, during the process of mounting it on the component, the surface seal is subjected to a mechanical tensional force directed substantially parallel to a peripheral direction of the component during one mounting phase and is subjected to a mechanical tensional force directed substantially transversely, preferably substantially perpendicularly, to a peripheral direction of the component during another mounting phase. 